Objective: A high prevalence of vitamin D deficiency (VDD) in gastrointestinal (GI) disorders and the role of vitamin D in the function of the gut have been shown previously. Therefore, we aimed to evaluated the VDD and the possible association of the GI symptoms severity and quality of life (QoL) score with the serum levels of vitamin D in irritable bowel syndrome (IBS).
Methods: A total of 90 patients with IBS based on Rome III criteria enrolled in the study from the tertiary referral university hospital. In addition, 90 sex- and age-matched healthy controls (HCs) were recruited. To measure the serum levels of 25(OH)D3, blood samples were taken from all the participants. Severity of clinical symptoms, IBS quality of life (IBS-QoL), and IBS symptom severity score (IBSSS) were assessed.
Results: In 66.7% of IBS patients, serum 25(OH)D3 concentrations were <20 ng/mL. The mean serum 25(OH)D3 of IBS patients was statistically (p < 0.05) lower vs. HCs. When different subtypes were analyzed, the serum 25(OH)D3 concentrations in diarrhea-predominant IBS were statistically (p < 0.05) lower as compared to HCs. Furthermore, the lower serum concentrations of 25(OH)D3 were associated (p < 0.05) with higher severity of abdominal pain and distention, flatulence, overall GI symptoms, and IBSSS. However, a direct significant association was seen between IBS-QoL and serum 25(OH)D3.
Conclusion: Results of this study showed a high prevalence of VDD in patients with IBS. In addition, VDD was associated with a higher severity of clinical symptoms and lower QoL in IBS.
Keywords: IBS severity score; Irritable bowel syndrome; clinical symptoms; health-related quality of life; vitamin D; vitamin D deficiency.